1. Field of the Invention
Coccidiosis is a well-known protozoan disease resulting from infection by one or more species of Eimeria or Isospora (for a summary, see Lund and Farr in "Diseases of Poultry," Fifth Ed. Biester and Schwarte, Eds., Iowa State University Press, Ames, Ia., 1965, pp. 1056-1096). When left untreated, the severe infections of coccidiosis lead to poor weight gain, reduced feed efficiency, high morbidity and mortality in fowl. The morbidity and mortality caused by coccidiosis infections create extensive economic loss when such infections are left untreated or unchecked. The control of this disease is, therefore, of paramount importance to the poultry industry. In the continuing efforts to find improved agents for the control of this disease, decreased toxicity is one of the desirable improvements.
2. Description of Prior Art
Antibiotic A204 factor I, from which the novel compounds of the present invention are prepared, is described in U.S. Pat. No. 3,705,238. The structure of antibiotic A204I has been determined by X-ray diffraction studies [Noel D. Jones, Michael O. Chaney, James W. Chamberlin, Robert L. Hamill and Sue Chen, J. Amer. Chem. Soc. 95, 3399-3400 (1973)]. This structure is shown in Formula I: ##SPC1##